Renal Cell Carcinoma

When someone hears the word cancer, they tend to get scared and start believing in all the things that they were told about this dreadful disease. Nowadays, with all the technological advancements and the huge developments that science has done, cancer has become a fairly treatable pathology. This treatment is only possible when we study the disease, its proper classification, the staging, the scans required for it, and the various treatment modalities in detail.

In adults, renal tumors are classified as benign and malignant. Renal cell carcinoma is a malignant type of cancer. One of the benign renal tumors is renal papillary adenoma, which is at risk of transforming into renal cell carcinoma(RCC). In children, there is only one type of renal tumor, the Wilms tumor.

Renal Cell Carcinoma is Also known as Grawitz Tumor/ Hypernephroma.it is also known as the radiologist’s tumor as it is INDICENTILTY FOUND ON RADIO INVESTIGATION. It is usually exclusively seen in adults. It is the Most common Malignancy of kidney. RCC is Most common in Males among 6-7^th decade. The Sporadic risk factor of Renal cell carcinoma is Tobacco (most common) and the other risk factor is Chronic Analgesic Nephropathy. There could also be an exposure to Cadmium and Asbestos in the early life which could result in RCC.

RCC

RCC Spreads via Hematogenous (blood) route. Thus, Examination of the Renal vein is important. We should remember at all times that All carcinomas spread via lymphatic route, except HCC & RCC. 

The Most common site of metastasis of RCC is lungs. Cannon Ball Secondaries are seen in RCC and Choriocarcinoma (variant of testicular tumor).

The Most common malignancy responsible for Osteolytic secondaries (Hypervascular) in Males: RCC. Pulsatile secondaries are seen in Renal cell carcinoma  and Follicular Carcinoma Thyroid. Renal cell carcinoma symptoms are quite genralized. The could easily vary from an Abdominal mass, Flank pain to a full blown episode of Hematuria (blood in urine). The Most common presentation is Hematuria. In advanced cases, Non- reducing Varicocele suggesting of Suspicious Varicocele can also be present Due to Thrombus from left RCC.

Renal cell carcinoma has a pseudo capsule. This disease also has a Prolonged period of stable disease and shows Response to biological response modifiers: IL2 and IFN alpha. Spontaneous Regression (the size of the tumour decreases ) is seen in Renal cell carcinoma.

We shall now discuss about the various Types of Renal cell carcinoma. Let us start from the very basics. 

Clear Cell Renal carcinoma is the Most common type of RCC.

It Arises from Proximal convoluted tubule. These carcinoma’s Cells contain glycogen & Lipids which are  washed away during staining due to which the Cell appears clear. There is Mutation of VHL  gene located on chromosome 3. If there is Deletion of chromosome 3p, it leads to Von Hippel Lindau(VHL) syndrome. VHL can have bilateral clear Renal cell carcinoma in which both kidneys are affected.

On microscopic examination we can observe Clear cells filled with fat & glycogen

When these clear cells are Stained, we get Fat OIL RED O positive and Glycogen- PAS positive. Also a grossly golden yellow (fat) tumor is visualized.

Chromophobe Renal cell Carcinoma

The next varient of RCC is Chromophobe Renal cell carcinoma.

In this variant we can see Multiple chromosomal losses (loss of chromosome 1,5,7). Birt-Hogg-Dube syndrome is RCC+ Fibrofoliiculoma. On a Microscopic level, it shows cells similar to plant cells with 

• Well-defined outlines
• Dark irregular nucleus known as Raisanoid nucleus
• Pheriperies have cytoplasm
• Around the nucleus there is Perinuclear Halo

For staining chromophobe renal cell carcinoma Hale’s Colloidal Iron positivity is used. This tumour has the Best Prognosis amongst all types of renal cell carcinoma.

Also Read: Trinucleotide Repeat Disorder (Fragile X Syndrome, Huntington's disease)

Next we study about the Papillary variant of Renal Cell Carcinoma. This is a very volatile topic for all the major examinations like NEET-PG and FMGE exam. It is usually Associated with

• Dialysis/hemodialysis patient
• Trisomy 7- Extra 7 chromosome that is C-MET gene or it could be hereditary
• Trisomy 17
• Loss of Y chromosome.

As we have read above HPRCC (Hereditary Papillary RCC) is caused due to Trisomomy of chromosome 7. There is another variant of this papillary renal cell carcinoma known as the HLRCC (Hereditary Leiomyomatosis Papillary RCC). this shows Lots of Leiomyomatosis due to Fumarate Hydratase Mutation. A very important fact about papilliary variant of renal cell carcinoma is that it is Associated with Dystrophic calcification known as the Psammoma bodies. This is a direct exam question. Psammoma bodies are seen in Papillary variant of RCC and PCT, Serous cyst adenoma of the  ovary and Meningioma.

Renal Papillary adenoma causes papillary RCC. One of the most important predictors of papilliary RCC is size. If the Size is <1.5cm then its an Adenoma, but if the Size is >=1.5cm then it is considered as PRCC.

The next important variant of Renal cell carcinoma is Bellini or collecting duct RCC. this variant has a very rare occurrence and has the Worst prognosis. It arises from the collecting duct. On a Microscopic level it shows Hobnail cells. Bellini renal cell carcinoma is Associated with Desmoplastic reaction.

Medullary Renal cell carcinoma is the fifth variant  of renal cell carcinoma. It is also a rare type of renal cell carcinoma. It is Associated with Sickle Cell trait patients (HbAS) & not with sickle cell anemia (HbSS)

Laast but not the least we have Pediatric variant of  Renal cell carcinoma. It is Associated with Translocation of Xp and TFE3 gene. Microscopically, it shows a combination of clear and papillary cells.

As renal cell carcinoma has so many variants it becomes very crucial to know what variant has affected the person so the patient can get best of treatment. There are various Investigations that can be done in order to know the specific variant but the Investigation of choice is CECT. the Investigation of choice for detecting tumor thrombus is MRI (to differentiate tumor thrombus from bland thrombus). However the GOLD STANDARD INVESTIGATION for IVC invasion is Inferior vena cava gram. 

Before we end this blog with the treatment of renal cell carcinoma we must very quickly go through the 8TH AJCC TNM CLASSIFICATION OF RCC. For someone in the first/ second year of MBBS, T stands for tumour, N denotes the lymph node status and M is for the metastasis.

N Classification

Stages

Fuhrman Nuclear Grading and robson staging is done for Renal cell carcinoma.

Treatment of renal cell carcinmoa is based on the localization of the tumour. If the tumour is localized then Radical nephrectomy is done with nepron sparring. Surgery is performed in cases of renal cell carcinoma (RCC) size up to 4cm by 4cm.

If the tumour has advanced locally or is metastasized then Radical Nephrectomy is done with no sparring. Monoclonal antibodies are also used. The 1st line agent is SUNITINIB and 2^nd line agent – IL-2+IFN-α. 

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